Question

1.Calculate the EAN of Co2(CO)6(RC=CR) complex.
2.Calculate the EAN of [Pt(NH3)5Cl]3+.​

Answer 1

Answer:   In [Co(NH3)6]3+=+3

Y=No of electrons gained by coordination =2×6=12

EAN of Co in [Co(NH3)6]3+=27−3+12=36 which

is equal to the atomic number of next higher noble gas which is (Kr,Z=36) Hence Co in [Co(NH3)6]3+ obeys EAN rule

Futher examples of complexes whose central atom//ion obeys EAN rule are given in Table 7.12

Explanation:

Answer 2

Given:

Given compounds are:

1.  $\[C{{o}_{2}}{{\left( CO \right)}_{6}}\left( RC=CR \right)\]$

2. $\[\left[ Pt\left( NH3 \right)5Cl \right]3+\]$  [Pt(NH3)5Cl]3+

To find:

We need to find the value of EAN or Effective atomic number.

Solution:

Effective number (EAN) in an exceedingly complex is defined as the total numbers of electrons present round the central metal ion.

1. EAN of $\[C{{o}_{2}}{{\left( CO \right)}_{6}}\left( RC=CR \right)\]$ complex

We know that, EAN = Atomic number (Z) – Oxidation number + 2 × Coordination number.

Let us consider as a chemical complex $\[C{{o}_{2}}{{\left( CO \right)}_{6}}\left( RC=CR \right)\]$.

The atomic number of the central atom is $(Co) = 27$

Oxidation number        = +2

Coordination number  = 6

EAN $=[27\text{ }-2+\left( 2\times 6 \right)]$    

       $\begin{align} & =25+12 \\ & =37 \\ \end{align}$

2. EAN of $\[\left[ Pt{{\left( NH3 \right)}_{5}}Cl \right]3+\]$ complex

We know that, EAN = Atomic number (Z) – Oxidation number + 2 × Coordination number.

Let us consider as a chemical complex $\[\left[ Pt{{\left( NH3 \right)}_{5}}Cl \right]3+\]$.

The atomic number of the central atom is $=78$

Oxidation number $=+3$      

Coordination number $=5$  

EAN $=78-3+(2\times 5)$

        $=75-3+10\\ =82$